Lowering pH in a Discus Fish Tank

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 *Discus fish like acidic water conditions, and your aquarium will run more efficiently when the pH is below 7.0 neutral. Bacteria is less prolific in acidic water, therefore in a Discus fish tank lowering the pH below neutral and into the acidic side will reduce bacteria. Acidic water on a molecular structure will convert toxic ammonia NH3 to a non-toxic form of ammonium Ion NH4. Aquarium ammonia testing kits will still read ammonia if present in the tank but if the pH is below 7.0 the ammonia will be non-toxic and less likely to harm the fish.

There are a number of acidifiers which can be added to your aquarium to reach the desired acidic pH levels. Powdered additive which are easy to handle and will not burn is sodium mono phosphate. Liquid acids like phosphoric, hydrochloric, or muriatic acid can burn skin therefore caution should be used while handling them.

Start by adding the acidifier of your choice to your tank, powder or liquid. If you’re using the powder add a heaping teaspoon to 50 gallons, if you’re using the liquid acid then start by adding 2.5 ml per 50 gallons. After adding the acidifier, the pH will immediately drop. After an hour or so the pH might climb back to below where you started. This is called, “pH bounce”. Depending on the buffering capacity or calcium in your water will determine how much and fast the pH will bounce back to where it was before adding the acidifier.

Continue adding the above dosage until you have reached the desired pH level. If you drop below the desired pH and wish to raise it, add a small amount of baking soda this will neutralize the acid to bring the pH up. 

Learn More: Discus Fish Blog

7th Jul 2024 Steve MacDonald

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